THE TRANSFORMATION TEMPERATURES OF HIGH-PURITY URANIUM. Work completed: December 31, 1957. Final Report--Metallurgy Program 3.1.1.

The transformation temperatures of high-purity uranium were determined by thermal analysis and dilatometry. Thermal analysis methods used include one in which the rates of heating and cooling were controlled by a differential thermocouple, and another in which repeated thermal analyses were made at independently controlled rates. The solid-state transformation temperatures and the logarithm of the heating or cooling rates at relatively low rates are related linearly. The extrapolated functions intersect at a point where the disturbing effects of hysteresis, superheating and undercooling disappear, i.e., at the equilibrium temperature. The mean transformation temperatures are 667 deg C for alpha in equilibrium beta and 775 deg C for beta in equilibrium gamma . The mean temperature for melting and freezing is 1132 deg C. (auth